The increase in bandwidth demand for optical links, such as links found in long-haul optical networks, is necessitating a rapid increase in the capacity of optical links. For instance, the capacities of optical channels in some optical communication systems are approaching about 100 gigabits per second (Gb/s). Moreover, to meet future capacity demands for optical networks, next generation optical communication systems are being designed to sustain capacities that reach multi-terabits per second (Tb/s). Although the demand to increase bandwidth and throughput continue to grow, designs for the optical systems are often constrained by cost, power, and size requirements. For example, the sampling rates of analog-to-digital converters (ADCs) and subsequent signal processing circuitry may be a limiting factor for increasing the operation speed of optical communication systems.
Typically, coherent optical receivers may utilize oversampling (e.g. the symbol sampling rates are higher than an optical system's baud rate) to enable fractionally spaced equalization of chromatic dispersion (CD) and/or polarization mode dispersion (PMD). In contrast to T-spaced equalizers, fractionally spaced equalizers (FSE) increase the tolerance against sampling phase errors and minimize noise enhancement arising from spectral nulls during aliasing. Specifically, a FSE may avoid noise enhancement by sampling the received signal at a rate higher than the symbol rate to limit the amount of aliasing in the received signal. In addition, an adaptive FSE may correct for sampling phase error on noise enhancement with interpolation. Unfortunately, current FSEs (e.g. T/2 spaced FSEs) may be relatively more complex, consume relatively more power, and/or relatively costly to implement within optical communication systems.